he Soviet Union today formally rejected President Reagan's new proposal for an interim accord on limiting nuclear missiles in Europe with Foreign Minister Andrei Gromyko describing it as "unacceptable" and "not serious."

Directly challenging Reagan's assertion that his proposal opens "the road to agreement, to peace," Gromyko said at a news conference: "No, this is wrong; it is not a road to peace or to agreement. The gulf between an agreement and these proposals will become even wider."

He said the U.S. proposals reflect a "deeply wrong" view in Washington that increased pressure on Moscow will increase the chances of reaching an agreement in Geneva.

"If the position of the United States remains as now, as it has been stated, then there are no chances for agreement," Gromyko said.

Despite flashes of controlled anger, Gromyko, 73, who was recently promoted to the post of first deputy premier, made an apparently calculated effort to avoid taking any responsibility for a possible breakdown of the Geneva talks.

Pressed to say whether Moscow would quit the Geneva talks on medium-range nuclear missiles when the scheduled deployment of 572 Pershing II and cruise missiles begins in December, he said: "This would be a sharply negative factor for Europe and the world as a whole, and the situation would be such that we will have to consider it most carefully, taking into account all factors and then take an appropriate decision."

The Soviets previously have talked informally about breaking off the parallel strategic arms negotiations in Geneva if the deployment of medium-range missiles goes ahead, according to U.S. officials.

Gromyko reiterated his government's objection to the exclusion of French and British missiles and U.S. forward-based strategic aircraft from the U.S. proposals.

Although most of the press conference dealt with the issue of nuclear weapons, Gromyko, who spoke in Russian, touched on other issues.

He made an unusually warm bow toward Israel by voicing the hope that "healthy" forces in Israeli politics would bring about a change in Tel Aviv's foreign policy. He said Moscow "does not share the views of extremist Arab circles" that want to "liquidate" Israel. He also said Syria, a close ally of Moscow, would be prepared to withdraw its forces from Lebanon if the Israelis do the same.

Gromyko also confirmed that his new post of first deputy premier makes him responsible for coordinating all aspects of foreign relations and gave a generally positive assessment of Sino-Soviet talks.

During the two-hour news conference, he underscored Moscow's view that the United States is responsible for a deterioration in the international climate, asserting that "we want to have better relations with the United States, but the United States does not want to improve its relations with the Soviet Union."

The Reagan administration, he added, is demanding that Moscow make "fundamental concessions at the expense of its security and its legitimate rights."

"This," he said, "is not going to happen."

The Soviet Union, he said, would not permit the Americans to "destroy" the existing strategic parity between the two countries.

"There should be no doubt that the Soviet Union will take measures to secure the principle of parity. We have material and intellectual resources for it."

Asked about Reagan's speech March 8 to the National Association of Evangelicals in Orlando, Fla., in which he referred to the Soviet Union as an "evil empire," Gromyko said such "insulting" remarks "do not lend authority to American foreign policy. You don't conduct affairs with other countries like this."

The news conference was carried live not only over Soviet television but also over Intervision, which covers Eastern Europe. Gromyko appeared to be very self-assured and physically fit as he stood the entire time, first delivering a long introductory statement without notes and then fielding questions.

What was new in Gromyko's presentation was a broader argument about medium-range nuclear weapons in Asia. For the first time, a senior Soviet leader said that the new SS20 nuclear missiles are being deployed in Asia to counter American nuclear delivery systems in Japan, South Korea, the Indian Ocean and the Persian Gulf.

He said the Soviet Union is "surrounded by a ring of military bases" where American "medium-range" nuclear weapons are deployed.

"These weapons," he continued, "have within their range the whole of Siberia, the whole of the Asian part of the Soviet Union, even its northernmost part of the Taimur Peninsula."

Gromyko said he was talking "only about medium-range weapons--one does not mean here the U.S. strategic weapons which exist and are deployed in the same areas that have been mentioned."

"Does not the Soviet Union, may one ask, have the right, for defense purposes, to have something to match those weapons," Gromyko said. Immediately answering his own rhetorical question, he said, "It does have this right."

He dismissed Reagan's demand that Soviet medium-range missiles in Asia be included in the Geneva negotiations by saying, "This demand alone makes agreement impossible."

Gromyko said that the Soviet Union would be prepared to withdraw some of the missiles from the European theater to Asia and "install them on sites from which they could not reach Western Europe," adding: "This is our business and our right."

What Reagan is now asking, he said, is that "these missiles should be eliminated." Gromyko added that "if this demand alone is taken, it already precludes agreement."

Speaking about Moscow's other objections to the Reagan proposal, he said that the British and French nuclear missiles are an integral part of the North Atlantic Treaty Organization and that "it is impossible to close our eyes to them."

"Imagine that a terrible tragedy had occurred and that, say, a nuclear-tipped British missile is in flight," Gromyko said. "Should it carry the label 'I am British?' If it delivers its charge, the people will die just as they would die from any other missile."

He said it would be an "absurdity" to ignore these weapons and not include them in the total count.

Gromyko also spoke about "hundreds" of land-based or aircraft-carrier-based American strategic aircraft in the waters "around Europe." He said these include at least six aircraft carriers with about 40 planes each.

Gromyko said that "in short Reagan's proposal is not serious. It is not designed to open opportunities for an agreement with the Soviet Union. This is why we call on Washington to adopt a more objective approach to this question, to renounce lopsidedness, to take into account all factors including the security interests of the Soviet Union.

"The line currently maintained at the Geneva talks is not a line for rapprochement, it is a line for moving away from agreement, a line for complicating the situation, for whipping up the arms race even further, worsening relations with the Soviet Union even further, securing an even faster growth of military budgets and containing the forces which favor the search for a common language with the Soviet Union to an even greater degree," Gromyko said.

Reagan's plan, he said, would give NATO a 2.5-to-1 superiority in the number of warheads over the Warsaw Pact.

He said Moscow has shown flexibility and generosity in the negotiations by not insisting on compensation for geographical factors that give the United States "an intrinsic advantage."

But "our policy" on "both strategic and medium-range weapons," he said, "is to preserve at all costs the parity, or if you will, the principle of equality and equal security that has evolved over many years.

"The U.S. policy aims at breaking and destroying this principle. We shall do everything with or without an agreement in order to preserve this principle," he said.

Gromyko described as false various U.S. statements that "serious talks are being conducted in Geneva" and complained about "many untruths, false assertions, exaggerations and misrepresentations" made by the Americans about "factual data."

Gromyko said that western governments "do not tell the truth to the people" and that the western media simply ignores Soviet positions and proposals. He said the media in the United States in particular are "hushing up" these facts.